Viscose coating and filling



Patent ed Oct; 8, 1935 UNITED -STATES PATENT OFFICE vIs'cosE coa'rmo ANDr nmNo Harold I. Huey, Saylesville, and William W.

Russell, East Providence, R. L, assignors to Sayles Finishing Plants,Inc., Saylesville, R. 1;, l a corporation of Rhode Island No Drawing.Application June 27, 1930, Serial No. 484,420

I x 1 Claims.

The present invention relates to filled or coated textiles, and to aprocess for producing the same; more particularly, it is concerned withthe provision of a permanent filling or coating upon ,a relatively lightweight, open construction, woven cotton fabric.

It has long been known that fibrous textile materials can be filled orcoated by means of viscose solutions, and that such fillings or coatingare permanentthat is to say, are so tenaciously retained by the textilematerial as largely to persist upon the latter for its natural life".However, the use of viscose, alone or with known additions (as forexample, a mineral filler") in the manner heretofore followed, has notalways aiforded the moat desirable results. instance, when used in thinsolutions, usually of relatively low cellulose content (e. g., a viscosecontent equivalent to about 4 to 3% cellulose content) the viscosedressing has unduly penetrated the yarn of the fabric, producing a thinfilling and an undesirable stiffness of the product. Such pronouncedpenetration of the,yarn by the viscose tends to leave any mineral fillerof the dressing composition on the outside of the fabric andinsuiilciently bonded thereto after the fixation of the viscose by thesmall amount of regenerated cellulose which has not penetrated into theyarn. Heavier (i. e., thicker) solutions of relatively high cellulosecontentwhile less penetrative of the yarn and, therefore, productive ofa more nearly complete filling of the fabric-yield a heavy boardynonextensible finish which generally is subject to cracking in anunsightly manner when stretched or flexed. Furthermore prior fillings orcoating on textiles have not always possessed the desired resistance towashing or laundering. 1

An object of the present invention is to provide a process forproducing, from a relatively light weight, open construction fabric, afilled fabric which (in comparison with the original transparent,pliable and flexible coating which "possesses a high permanency towardwater.

" to a filling or coating composition consisting essentially of anaqueous viscose solution inv amounts necessary to produce a suitablepartial 10 coagulation of the viscose and the viscose mixture in thistransitory, induced critical state is applied and fixed on a textilematerial in a known manner, a filled or coated textile is produced whichpossesses very superior qualities."15 In the case where the object isprimarily that of filling a low grade textile to enhance its fullness,weight and appearance, these superior qualities include; (a) a pleasant,soft, flexible feel or handle; (b) an appearance in nature entirely 20similar to that of a high grade but unfilled textile; (cYa goodextensibility, as shown by freedom from cracks when stretched; (d) ahigh degree of permanency toward repeated laundry washings. In the casewhere luster or brilliancy 25 is a primary or added consideration, it isreadily I possible to produce coated or filled textiles which possess inaddition to the above mentioned qualities a high brilliancy and lusterof good permanence. In the case where it is desired to pro- 30 duce atransparent coating such as upon a very open or lowgrade textile ortextile fabric, the qualities conferred by the process include: (a)

a highly uniform transparent brilliant coating; (b) a high pliabilityand suppleness; (c) an ex- 35 cellent permanence toward water.

Partial coagulation of the viscose filling or coating mixture by heat oraging at room temperature or above or below, is diflicult to control, isirreversible, and filled or coated textiles pro- 40 duced therefrom lackcertain merits, conferred by the presence of a coagulant. Thus thepresence in the dressing of the coagulating agent used to produce theaforesaid incipient coagulation favorably modifies the action of thefixing bath (e. g., solution of acid, acid salt, or the like), giving inpart to the product produced the desirable properties previouslymentioned. Also, during an acid fixation of the viscose,sulphurcontaining compounds are much more easily removed,thereby greatlyfacilitating any subsequent bleaching process. The amount of reagentrequired to bring about a certain degree of coagulation of the viscosewill-depend upon the chemical and physical nature of the reagent andalso upon the quality, temperature and age of the viscose. While theaction of the added coagulating or precipitating agent is mainlyphysical in nature, it may be accompanied by chemical effects such, forinstance, as the displacement of ammonia from added ammonium salts byinteraction with caustic soda present in the viscose solution. The factthat the partial coagulation induced by added reagents is oftenreversible between limits, is of no small practical advantage inmanufacture.

In the preparation of a viscose filling or coating mixture according tothe present invention, a coagulating agent is added to the viscosemixture until a degree of coagulation and thickening is achieved, suchthat the desired distribution of deposited regenerated cellulose betweenthe exteriors and interiors of the yarns and fibers of the textile willoccur when the filling or coating composition is applied and fixed in aknown manner. What distribution or positioning of the coating or fillingis desired, will depend in a measure upon the textile and its proposeduses. Where the permanent filling of a. low grade fabric is the primaryobject, partial coagulation is brought to such a point that the viscosefilling mixture penetrates into the yarns and fibers of the fabric onlyenough to firmly secure the filling to them and not enough to render thefabric unpleasantly harsh and stiff, while on the surfaces of the yarnsthere remains ample substance to firmly bond talc or particles of a likefiller to the fabric. By working in this manner with an incipientlycoagulated viscose, a filling composition of 3 to 4% cellulose contentmay be used to produce a product which is completely filled, yet has apleasant handle-not too firmand is extensible and flexible withoutcracking or splitting of the filling, and these properties remainsubstantially unchanged through repeated laundry washings. Theseproperties are enhanced if, prior to fixing, the filled or coated fabricis heated and/or dried, whereby coagulation is slowly completed and aregeneration of cellulose begins due to the accelerated action of theadded coagulating agent at the higher temperature and as itsconcentration is increased during drying. The use of a non-coagulatedviscose of the equivalent thickness and viscosity would require acellulose content in the neighborhood of '7-9% and would lead to theproduction of a heavy, stifi, non-extensible filling, subject tounsightly cracks. Without incipient coagulation, the use of a viscosesolution of 3-4% cellulose content would yield, due to excessivepenetration, a stiff, harsh product with any filler insecurely bonded toit and, therefore, possessing poor washing qualities. The devices of theprior art have proved inadequate to remedy the foregoing defects to asubstantial degree. The incorporation of such foreign materials assoaps, oils, fats, waxes, and softeners have proved generallyinadequate. There may be used an insoluble metallic soap such as thatproduced according to the process of our co-pending application SerialNo. 283,734 in conjunction with the incipiently coagulated viscosefilling or coating mixture described in the present invention.

When the production of silk-like or lustrous efiects is an added orprimary object the present invention is particularly applicable. Theready control of the positioning and distribution of the regeneratedcellulose coating or filling with respect to the supporting textilewhich the process affords, makes possible the production of highlylustrous, thin, flexible, extensible, coatin'gs whose properties persistthrough numerous washings. Luster or silk effects are usually producedin the absence of a filler such as talc.

Where the production of a transparent coating or filling on a very lowcount open fabric is desired, the present invention is also of especialapplication. By the use of partially coagulated viscose a thickness andviscosity can be imparted to the coating mixture, even though it beofonly 1 3-4% cellulose content, such that large interstices between yarnsare readily bridged when the coating mixture is spread and fixed on thecloth in a known manner. There results a fabric covered with a thin,uniform, flexible, highly trans- 1 parent coating which possesses goodresistance toward water. And since all the openings or intersticesbetween the yarns have been closed, the fabric is rendered substantiallyimpervious and substantially air-tight; By water-proofing this 2material'in a known manner the fabric is'readily rendered impervious sothat aqueous solutions as well as vapors and solids cannot pass throughit agents are: glucose, monohydric alcohols such as ethyl alcohol andmethyl alcohol, polyhydric alcohols such as glycerine and glycol,sugars, weak acids typified by acetic, acid and water-soluble salts,including chlorides, nitrates, acetates, thio- 3 cyanates and sulfatesof the alkali and alkaline earth metals. It is preferred to use,however, for many purposes sodium chloride or ammonium acetate ascoagulating agent because of their relative cheapness and efficiency.The viscose 3 dressing mixture is suitably partially coagulated by theaddition of one or more of such coagulating or precipitating agents orthe like and when in this critical state, applied in a known manner tothe fabric after which the viscose readily may be completely coagulatedby heat, steam, or treatment with appropriate acid or acid saltsolutions or the like.

Various modifications of known filling and coating technique may be usedin conjunction with the present invention. Limits to the concentrationand composition of viscose plus coagulant filling or coating mixturesare not set and may be varied between fairly wide limits and yet producedesirable results. The degree to 5 which the viscosity is increased bythe coagulating agents may be varied to best suit the fabric to befilled. Unbleached, non-absorbent fabrics need not have the fillingcoagulated to such an extent as when in the bleached or absorbent 5state. 'We have observed that in many cases the coagulation treatmentshould increase the time it takes a ball to fall a given distance,twenty to thirty times. However, in many in- Among operable coagulatingor precipitating 25 stances the filling mixture must be so much 60thickened that even a large (1" diameter) heavy ball will not fallthrough it. In no case, however, is coagulation carriedso far that aglassy,

non-sticky filling or coating composition is placed upon the goods. Inthe following examples are 5 given a limited number of representativeapplications of the invention.

Example 1 aommo phurized with 12 lbs. carbon bisulphide for hours at 22C. Water and caustic are added v until a solution containing celluloseand cyanate.

4.6% NaOI-I (on the pulp) is obtained. For thisexample, the viscose isaged for '70 hours at about 12 C. (This aging is not necessary butmay-be convenient.) .25 lbs. of' the above 10% viscose is mixed with 25lbs. talc wet outwith 35 lbs. water and 90 lbs. sodium chloride solution(containing 14 lbs. NaCl) added slowly, making a 4% cellulose solution.The mixing is continued at a' suitable temperature until the massthickens. The viscosity is taken with a 1" solder ball weighing 64.2grams. 'The time required to fall 6" is about 60 seconds. To fall thesame distance in a 4% viscose solution containing an equal amount oftalc, but no NaCl, it takes 2 seconds. The fabric (68x 72 4.75)printclothhaving. been boiled, bleached and dried, is filled on a backfillingmachine, dried, fixed with a 5% H2804 solution at about 60 C., for a fewminutes, then washed, dried and finished.

Example 2 Into 25 pounds of 10% viscose solution there is added andthoroughly mixed 5 lbs. of talc which has been wetted out with 5 lbs. ofwater. :Io this mixture there is slowly added, with agitation, asolution of 1.5 lbs. of calcium thiocyanate (B. P. 135 C.) 1 lb. ofacetic acid 28%, and 25 lbs. of water. The resulting thick masscontaining about 4% of cellulose is applied to the fabric (bleached orunbleached) by means of a backfilling machine, dried, fixed in a 5%sulfuric acid bath, washed, bleached and finished.

Example 3 To 25 lbs. of 10% viscose and 5 lbs. of talc lb. of calciumchloride dissolved in 30 lbs. of water is slowly added and theresultingthickened mixture is applied as indicated in Example 2.

Example 4 25 lbs. 'of 10% viscose is mixed with 40 lbs. of watercontaining 1.5 lbs. of ammonium thio- After a short time (say, 1 hour)the mixture begins to thicken. The viscosity is taken with a steel ballweighing 3.13 grams, falling 11%". The time requiredis 387 seconds. In a4% viscose solution containing no ammonium chloride, this ball fell in17 seconds. The

mixture is then spread upon cloth, dried, fixed with sulfuric acid,washed, and run through a solution of hot sodium sulphide (todesulfurize it). On drying under tension there results a transparentfilm which may be kept flexible by an application of some hygroscopicagent such as glycerine.

Example 5 25 lbs. of 10% viscose is mixed with 40 lbs. of watercontaining 2 lbs. of ammonium acetate, and the resulting mixture istreated and used in the manner set out in Example '7.

In connection with the foregoing examples, it is to be noted that it maybe found desirable for certain purposes, to further modify the fillingsor coatings by incorporation therewith of oils, fats, waxes, soaps,sulfonated oils or fats, glycerine, softeners, pigments, dyestuffs,metals, minerals, wood pulp and other substances whose use is known tothe art.

It appears that the present invention involves two factors which resultdirectly or indirectly from the use of aviscose filling or coatingmixture incipiently coagulated or precipitated to a critical degree bythe use of a coagulating or precipitating agent-suitable in nature andamount,'and contained in said mixture. First: the positioning of thefinal deposit of regenerated cellulose with respect to the supportingtextile, and .any additional filler, e. g., talc, pulp, etc., is underaccurate and easy control and, therefore, may be readily varied asdesired, to give the most advantageous results. Second: the presence and10 efiect of a. coagulating or precipitating agent in the filling orcoating composition favorably modifies the physical characteristics ofthe final deposit of regenerated cellulose obtained therefrom. Whatresults are considered advantageous and 15 what characteristicsparticularly to be desired, will depend in a large measure upon theproduct which is to be produced and such considerations have alreadybeen dealt with at length in the preceding paragraphs. 20

We claim:

1. In a process for the production of a permanently filled or coatedtextile, involving the op- .xanthate containing an added coagulatingagent, said solutionhavlng a cellulose content of from about 3% to about4% and a viscosity at least equal to that of an untreated and unagedcellu- 85 lose xanthate solution having a cellulose content of from 7%to 2. In a process for the production of a permanently filled or coatedfabric involving the operations of applying to the fabric a coating of a40 composition consisting principally of viscose and thereafter fixingthe coating on the fabric by regenerating cellulose from. the viscose,the improvement which consists in applying to the textile, while in astate of incipient coagulation, a 45 dressing composition consistingessentially of a viscose solution containing an added coagulating agent,said solution having a cellulose content of from about 3% to about 4%and a viscosity at least equal to that of an untreated and unaged 50cellulose xanthate solution having a cellulose content of from 7% to 9%.

3. Process for the production of a permanently filled or coated textilematerial which comprises applying to the textile material a coating of acomposition consisting essentially of viscose incipiently coagulated bythe presence and effect of a previously added coagulant, said viscosehaving a cellulose content of from about 3% to about 4% and a viscosityat least equal to that of an untreated and unaged viscose having acellulose content of from 7% to 9%, and thereafter fixing the coating bycompleting the coagulation of the viscose and regenerating cellulosetherefrom.

4. Process for the production of a permanently filled or coated fabricwhich comprises preparing a coating composition containing cellulosexanthate'and of about 3% to 4% cellulosecontent and a coagulating agentin amount insufilcient to effect precipitation of the cellulose xanthatebut sufiicient to materially increase its tendency to precipitate and toincrease the viscosity of the xanthate to at least that of an untreatedand unaged cellulose xanthate having a cellulose con- I tent of from 7%to 9%, applying a coating of the compositidn to the fabric while thecellulose xanthate is in a state of incipient coagulation and fixing thecoating by regenerating cellulose therefrom.

5. Process as defined in claim 4, characterized in that the coagulatingagent is a member of the group consisting of soluble ammonium salts andsoluble thiocyanates.

6. Process for the production of a permanently filled fabric whichcomprises preparing a dressing composition containing from 4% to 3% ofcellulose in the form of viscose and a suitable watersoluble salt in anamount sumcient to increase the viscosity to at least that of anuntreated and unaged cellulose xanthate having a cellulose content offrom 7% to 9% and to materially increase the tendency of the celluloseto precipitate but insufficient to cause its complete precipitation,applying a coating of the composition to the fab ric, and fixing thecoating by a regeneration of cellulose therefrom.

7. As a new product, a pliable and flexible fabric of open constructionthe fabric having its interstices bridged and substantially filled by awater-insoluble continuous film of coating consisting essentially ofregenerated cellulose adhering tenaciously to the surface of the fabricand extensible and flexible with the fabric without cracking orsplitting, which product is producible by applying to a surface of thetextile, while in a state of incipient coagulation, a dressingcomposition consisting essentially of a solution of cellulose xanthatecontaining an added coagulating agent, said solution having a cellulosecontent of from about 3% to about 4% and a viscosity at least equal tothat of an untreated and unaged cellulose xanthate solution having acellulose content of from 7% to 9%, and regenerating cellulose from thedressing composition in situ.

HAROLD I. HUEY. WILLIAM W. RUSSELL.

